Establishment = 9. an established church, esp. the Church of England
Established church = a church that is recognized by law, and sometimes financially supported, as the official church of a nation.
and perhaps most enlightening of all-
Establishmentarian = 3. a supporter or adherent of the principle of the establishment of a church by state law; an advocate of state religion.
and as for respect:
respecting = regarding; concerning [1725-35]
Thus, the First Amendment, "Congress shall make no law respecting the establishment of religion....' could be read as - "Congress shall make no law regarding the creation or implementation of an official state religion.", or so I was taught some forty plus years ago.